How to pause execution of push button until specific trigger received by NI device?

I have a user interface (GUIDE) in which the user is supposed to press a push button to initiate analog output to NI devices:

NIao = daq.createSession('ni');
addAnalogOutputChannel(NIao, 'Dev1', ['ao', handles.laser.port], 'Voltage');
NIao.Rate = 1000;
warning('off', 'all')

In my setting, I need the user to press the push button and then I need the program to wait with the execution until it receives an input trigger from the NI device. I thought I could use startForeground(s) for the input from the NI device:

NIai=daq.createSession('ni'); 
addAnalogInputChannel(NIai,'Dev1',1,'Voltage');
NIai.Rate = 1000;
startForeground(NIai)

which would then block the following code, that is, the output, from being executed:

queueOutputData(NIao, handles.laser.laserAna);
NIao.startBackground();

However, I am not sure how to define the session operation as "complete" since I need it to wait for a certain input (trigger) from the NI device, that is, a reduction in voltage to ~ 0 V. But perhaps waitfor would also be a work around?

Thank you in advance.

[Walter Roberson]

Perhaps yu could use a trigger? https://www.mathworks.com/help/daq/acquire-voltage-data-using-a-digital-trigger.html

[Sophia]

Great. Thank you! Worked perfectly.

[Walter Roberson]

Could you post your adjusted code, as an example for others? (It would make sense to post it as an Answer to your own Question)